Electron discharge device base structures



April 9, 1957 w. T. MlLLlS 2,788,503

ELECTRON DISCHARGE DEVICE BASE STRUCTURES Filed July 27, 1953 g n r ,4.

Ill,

ELECTRON DISCHARGE DEVICE BASE STRUCTURES Walter T. Millis, Owensboro,Ky., assignor to General Electric Company, a corporation of New YorkApplication July 27, 1953, Serial No. 370,548

3 Claims. (Cl. 339-94) My invention relates to electron dischargedevices and pertains more particularly to base structures therefor.

Air-borne radio apparatus is being carried to higher altitudes and isaccordingly being exposed to greatly reduced atmospheric pressures. As aresult of the reduced pressures, corona develops at relatively lowvoltages and seriously interferes with normal operation of theapparatus. Pressurizing of the apparatus to prevent corona developmentrequires sealed containers which are costly and further requirescomplicated auxiliary equipment to maintain the pressure within thecontainers at desired values.

A particularly vulnerable location at which appreciable corona losseshave been found is at the end of the base pins of glass and metal tubesat the points where the pins are riveted to the base. The rivetingoperation ordinarily leaves a rough sharp-pointed burr and are overbetween the burrs of adjacent pins is greatly enhanced, particularly atthe reduced pressures of high-altitude flight.

Heretofore, it has been proposed to reduce the deleterious effects ofcorona and are over by forming wells and ridges in the tube base toincrease the path length between adjacent leads. While such cxpedientshave somewhat reduced danger of corona and are over it has been foundthat for flight at higher altitudes, such as those achieved by modernunmanned craft, the effect cannot be sufiiciently eliminated by priorknown means.

It is, therefore, a principal object of my invention generally toimprove the construction of base-lead assemblies of electron dischargedevices.

Another object of my invention is to provide an improved electrondischarge device base that incorporates means to prevent dischargebetween adjacent conductors even under conditions of low atmosphericpressure. Further objects and advantages of my invention will becomeapparent as the following description proceeds and the features ofnovelty which characterize my invention will be pointed out withparticularity in the claims annexed to and forming part of thisspecification.

In carrying out the objects of my invention I provide an electrondischarge device comprising an envelope member including a header havinga plurality of lead-in conductors sealed therethrough and an insulativebase including a plurality of hollow terminal prongs extending throughand secured in the base for receiving the lead-in conductors.Surrounding one or more of the lead-in conductors and compressed betweenthe header and the base is resilient sheet insulating material forpreventing discharge between the conductors. w p i For a betterunderstanding of my invention reference may be had to the accompanyingdrawing in which Fig. l is an elevational view of an electron dischargedevice partially broken away to illustrate one form of my inventionincorporated therein;

Fig. 2 is an enlarged fragmentary sectional view illustrating in detailthe form of my invention shown in Fig. 1;

United States Patent i 2,788,503 Patented Apr. 9, 1957 ice Fig. 3 is aplan view of a gasket employable in a second form of my invention; and

Fig. 4 is fragmentary sectional view illustrating in detail the secondform of my invention.

Referring to the drawing, I have shown in Fig. 1 an electron dischargedevice generally designated 1. The device 1 comprises a generallytubular envelope member 2 and a base 3.

The envelope member 2 is formed of any suitable material such as glass,and hermetically houses an electron discharge structure generallydesignated 4. The structure 4 will not be described in detail hereinsince it may be any one of numerous types of structures employable inelectron discharge devices such asthat indicated by 1. One end of theenvelope member 2 is formed to include a header 5. Formed on the innerand outer faces of the header 5 are registering pluralities of bosses 6and 7, respectively. The bosses 6 and 7 correspond in number to thenumber of conductors to be led into the member 2 for connection to thestructure 4. However, in order to simplify illustration only one of eachof the bosses 6 and 7 have been shown.

The base member 3 is formed of any suitable rigid insulating materialsuch as Bakelite or Micanol and includes a recess 8 for receiving theheader 5 of the envelope member 2. Further formed in the base member 3and in the bottom of the recess 3 is a plurality of other recesses orwells 9. The wells 9 correspond in number to and receive the bosses 7formed on the outer face of the header 5. As best seen in Figure 2, thediameter of the bosses 7 is less than that of the wells 9 and the bossesextend into the wells an extent less than the depth of the wells. Thus,the bosses are spaced from all of the walls of the wells, the purposefor which will be brought out hereinafter.

Provided for being electrically connected to the structure 4 in themember 2 and extending through the bosses 6 and 7 in a sealed manner isa plurality of lead-in conductors 10. Provided for receiving and havingthe external portions or ends of the lead-in conductors 10 electricallyconnected therein is a corresponding plurality of hollow terminal prongs11. As seen in the drawing, the external portions of the conductors 10are relatively longer than the prongs 11, and thus the conductors 10 areadapted for maintaining the header 5 spaced from the bottom of therecess 8 in the base 3. The purpose for this will also be brought outhereinafter. The terminal prongs 11 each extend through the base member3 at the bottom of one of the wells 9 formed therein. As best seen inFig. 2 the prongs 11 are secured to the base member through riveting.This is accomplished by forming the shanks of the prongs with shoulders12 for engaging the exterior of the base and by upsetting the edges ormarginal portions of the prongs inside the wells 9, in the mannerindicated by 13. Thus, the marginal portions of the prongs 13 areextended outwardly for engaging the face and cooperating with theshoulders 12 to secure the prongs in the base. Also formed on the base 3is an aligning plug 14 which is well-known in the art and facilitatesinsertion of the prongs in a socket.

In the arrangement described to this point the prongs 11 areelectrically connected to the lead-in conductors 10 which in turn aresimilarly connected to the structure 4, adapting the device for currentfiow into and out of the envelope member through the lead-in conductors10. Now, when the above-described device is subjected to greatly reducedatmospheric pressure, as when employed in air-borne equipment carried torelatively high altitudes, there is a tendency for corona to develop andarc over to result between the lead-in conductors 10 at relatively lowvoltages. This undesirable tendency is greatly enhanced bythesharp-po'inted burrs formed on'the mar- -Will-.be mi'nimized by thewells 9 which increase the path lengths between adjacent lead-inconductors. To pre- -vent the development of corona-andarc over ordischarge between the leads and thereby increase the altitude range ofequipment includinglthe'device 1, I have provided meansfor-increasing-theelectrical resistance between ad- 'iacent leads.

The just-mentioned means for preventing discharge between the lead-inconductors comprises resilient material, such as silicone rubber, insheet-form surrounding one r=more of the lead+in conductors andcompressed in the space provided between the header and the base.

lAsfseenin Figs. 1 and 2-the resilient sheet insulating material can beformed as grommets 15. In grommet form the insulating material is fittedaround one or more and preferably each-lead-in conductor ltlandcompressed between the corresponding bosses 7 and the bottoms of thecorresponding wells 9. 'ltwill benoted that compression of the grommetresults in the forcing of insulating material intothe space between theside-wall portions of the bosses and'wells, thereby enhancing theinsulative action. Thus, the rough marginal portions or rivet ends .13of the prongs 11 and 'the portions of the lead-in conductors between theends of the bosses 7 and the bottoms of the wells 9 are-encased orembedded in the resilient insulating material of which the grommets 15are formed, whereby discharge between the lead-in conductors isprevented.

The resilient sheet insulating material can also be formed as a singlegasket -16 in the manner shown in Figs. 3 and 4. The gasket 16 may bepunched or cut to theconfiguratio'n of Fig. 3 and to include a pluralityof apertures 17 corresponding to and adapted for receiving the lead-inconductors 10. The gasket 16 may also include a central aperture 18 forreceiving an exhaust tube (not shown) on the header 5. In the gasketform the insulating material has one or more and preferably all of thelead-in conductors extending therethrough and is compressed between theheader 5 and the base 3. In this form, portions of the gasket -16,indicated by 20,

are disposed and compressed between the bosses 7 and the Wells 9. Thus,as in the form of Figs. 1 and 2 the rough marginal portions or rivetends13 of the prongs 11 and the portions of the lead-in conductors betweenthe bosses and the bottoms of the wells-are encased or embedded in theresilient insulating material of which the gasket is formed wherebydischarge between the leadin conductors is prevented. Additionally, inthe form of my invention including the gasket 16 additional resistanceto discharge between the lead-in conductors is attorded by the portionsof the gasket surrounding the portions 20 and compressed between thebottom and top sides of the header 5 and the base 3, respectively.

While I have shown and described specific embodiments of my invention Ido not desire my invention to be limited to the particular form shownand described and I intend by the appended claims to cover allmodifications within the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent ot the UnitedStates is:

1. An electron discharge device comprising; a generally tubular envelopemember including a header at one end having a plurality of lead-inconductors sealed therethrough, a base of rigid insulating materialincluding a plurality of hollow terminal prongs extending therethroughwith the marginal portion of said prongs extending outwardly andengaging said base, said lead-in conductors having external portionsextending respectively into different ones of said terminal prongs andhaving the ends of said external portions secured to said terminalprongs, said external portions of said conductors being relativelylonger than said prongs, thereby to maintain said header completelyspacedfrom said base, and resilient sheet insulating materialsurrounding'one or moreof said lead-in conductors and compressed betweensaid header and said base for preventing discharge between saidconductors.

2. An electron discharge device comprising; a generally tubular envelopemember including a header having a plurality of bosses formed thereon, aplurality of lead-in conductors extending through and sealed in saidbosses, a baseof rigid insulating material including a plurality ofwells'receiving said bosses, saidbossesbeing smaller in diameter thansaid wells and extending into said wells anextent less than thedepthofsaid wells, whereby said bosses-are-positioned in said 'wells inspaced relation to all of the walls thereof, a plurality of hollowterminal prongs extending through said base at *the 'bottoms of saidwells with the marginal portions of said prongs extending outwardly andengaging said base, said lead-in conductors extending respectivelyintoditferen't ones of said terminal prongs, and a compressed gasketofresilient sheet insulating material interposed between said header andbase, said gasket including portions surrounding one or more of saidlead-in conductors and being compressed between the corresponding bossesandwells for preventing discharge between said conductors.

3. 'An electron discharge device comprising; a generally tubularenvelope member including a header having a plurality of bosses 'formedthereon, a plurality of lead-in conductors extending through and sealedin said bosses, a base of rigid insulating material including aplurality of wells receiving said bosses, said bosses being smaller indiameter than said wells and extending into said wells an extent lessthan the depth of'said wells, whereby said bosses are positioned in saidwells in spaced relation'to all of the walls thereof, a plurality ofhollow terminal prongs extending through said base at the bottoms ofsaid wells with the marginal portions of said prongs extending'outwardlyand engaging said base, said leadin conductors extending respectivelyinto different ones of said terminal prongs, and individual grommets of'resilient sheet insulating material surrounding'eachof said lead-inconductors, said grommets being disposed and compressed between saidbosses and the bottoms "of said wells for preventing discharge betweensaid conductors.

References Cited in-the file of thispatent UNITED STATES PATENTS2,024,547 Strongson Dec. 17, 1935 2,235,135 Andresen Mar. 18, 1 9412,297,828 Flatford Oct. 6, 1942 2,383,909 Buchanan Aug. 28, 119452,383,926 White Aug. 28, 19 45 2,470,518 'Orr May 17, 1949 FOREIGNPATENTS 587,643 Great Britain May 1, 19 17

